Seal for LP gas cylinder valve

ABSTRACT

An O-ring seal for installation in an LP gas cylinder valve with a method and tool for installing the seal in the valve. The LP gas valve includes an outlet passage opening into a chamber within the main body of the valve which in turn is connected to a passage which opens into a cylinder tank. The outlet passage threadedly receives a hollow cylinder through which a stem projects. The stem includes an enlarged bullet shaped end projecting through an annular seat within the outlet passage and into a tapered portion of the outlet passage. An O-ring seal is installed on the annular seat effecting a seal between the valve and stem while spacing the enlarged bullet shaped end of the stem from the tapered portion of the outlet passage. A plate wrench has a hexagonally shaped hole through which a hexagonally shaped nut on the hollow cylinder projects. The wrench is used to tighten the stem with respect to the O-ring seal. Means are provided on the plate wrench for storing spare O-ring seals.

This is a continuation of application, Ser. No. 599,323, filed July 28,1975 and now abandoned which was a divisional of application, Ser. No.478,059, filed June 10, 1974, now U.S. Pat. No. 3,929,042.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is in the field of LP cylinder valves and morespecifically, methods and tools for effecting a seal between the valveand a stem connected to the outlet of a valve.

2. Description of the Prior Art

A standard valve has been adopted in the LP gas cylinder industry forcontrolling the flow of LP gas from the cylinder tank. The valve,commonly referred to as a POL fitting, has a bottom threaded portionwhich is mounted into the LP cylinder tank. The valve also includes aninternally threaded outlet with means provided within the valve body tocontrol the flow of LP gas from the tank and through the chamber to theoutlet of the valve. In addition, a safety mechanism is provided on thevalve to allow escape of LP gas in the event that the pressure withinthe tank exceeds a predetermined value.

The outlet of the valve includes an internally threaded tube having aninner tapered portion opening into a chamber within the valve body. Theoutlet of the valve is connected to an external pipe by means of ahollow stem having an inner enlarged bullet shaped end forced intocontact with the tapered inner portion of the outlet. The metal contacttherefore provides a seal between the outlet and stem. Such a stem isreferred to commonly as a hard nosed male connector. Such connectorscost approximately 85¢ per unit. An alternate version is identical withthe hard nosed male connector with the exception that an O-ring ismounted to a groove provided in the enlarged bullet shaped end of thestem thereby preventing metal to metal contact between the bullet shapedend and the outlet with the O-ring being forced between and against theenlarged bullet shaped end and the tapered portion of the outlet. TheO-ring is positioned within the tapered portion. Such a connector iscommonly referred to as a soft nosed male connector and may be purchasedfor approximately $5.00 per unit.

The soft nosed male connector is advantageous in that the connector maybe repetitively connected and disconnected from the LP gas valve withoutdamage or marring resulting from the metal to metal contact between theenlarged end of the stem and the tapered portion of the valve. Adisadvantage of the soft nosed connector is the relative higher cost ascompared to the hard nosed male. The soft nosed connector is alsoadvantageous over the hard nosed connector since less torque is requiredto effect the seal with the O-ring version thereby alleviating thenecessity for large wrenches for installing the soft nosed connector.

As a result of the lower cost of the hard nosed connector, mostconnectors in use are of the hard nosed variety. Disclosed herein is aseal and method for converting a hard nosed connector into a soft nosedconnector by inserting an O-ring between the enlarged bullet shaped endof the stem and the tapered portion of the outlet of the valve therebypreventing the metal contact even though a seal is achieved. Alsodisclosed is a wrench for tightening the connector which includes meansfor storing spare O-rings within the wrench.

SUMMARY OF THE INVENTION

One embodiment of the present invention is in a liquid petroleum valveand the tank combination including a tank for holding liquid petroleumwith the tank having an outlet aperture, the combination furtherincluding a liquid petroleum valve threadedly received by the outletaperture, the valve having a main body with a chamber formed therein andan inlet passage leading from the outlet aperture to the chamber, themain body further including an internally threaded outlet tube with anoutlet passage extending therethrough opening into the chamber with thevalve including means mounted to the main body operable to control flowof liquid petroleum from the tank through the chamber and the outletpassage, the outlet passage including an inner tapered portion and anouter internally threaded portion with an annular seat disposedtherebetween, the valve having an externally threaded hollow cylinderthreadedly received by the internally threaded portion and a hollow stemslidably extending through the hollow cylinder, the stem includes abullet shaped enlarged head projecting through the annular seat into theinner tapered portion being secured therein by the hollow cylinderwherein the improvement comprises an O-ring seal seated on the annularseat with the enlarged head forced through and against the O-ring sealeffecting a fluid tight seal between the enlarged head and the main bodyby the hollow cylinder forcing the enlarged head against the O-ring sealwith the enlarged head being spaced from the inner tapered portion.

Another embodiment of the present invention is an O-ring seal storagewrench comprising a plate having a first hole extending therethrough forcomplementarily receiving a nut to be tightened, the plate having meansthereon operable to releasably hold at least one O-ring seal.

Yet another embodiment of the present invention is a method of changinga hard nosed liquid petroleum cylinder valve to a soft nosed liquidpetroleum cylinder valve comprising the steps of untightening andremoving a male hollow valve stem having an enlarged nose end from aliquid petroleum cylinder valve, the valve having an internal taperedportion and an annular seat, inserting an O-ring seal into the valve andonto the annular seat through which the stem projects, mounting the stemonto the valve, extending the stem through the seat and ring, keepingthe enlarged nose end spaced apart from but adjacent to the taperedportion, and tightening the stem on the body forcing the enlarged noseend against the O-ring seal effecting a seal between the stem and thevalve.

It is an object of the present invention to provide an improved LP valvecylinder combination having an improved seal between the valve outletand a tube connected thereto.

A further object of the present invention is to provide a tool forstoring spare O-ring seals and for use in tightening a tube to theoutlet of an LP gas valve.

Another object of the present invention is to provide a method ofchanging a hard nosed LP cylinder valve to a soft nosed LP cylindervalve.

Related objects and advantages of the present invention will be apparentfrom the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an LP gas valve and cylinder combinationincorporating the present invention.

FIG. 2 is an enlarged fragmentary top view of the LP gas valve shown inFIG. 1 and having a hard nosed connector secured thereto.

FIG. 3 is the same view as FIG. 2 only showing a soft nosed connectormounted to the valve body.

FIG. 4 is an enlarged fragmentary side view of the LP gas valve of FIG.3.

FIG. 5 is a plan view of a plate wrench incorporating the presentinvention.

FIG. 6 is an enlarged cross sectional view taken along the line 6--6 ofFIG. 5 and viewed in the direction of the arrows.

FIG. 7 is a plan view of an alternate embodiment of the plate wrench.

FIG. 8 is an enlarged cross sectional view taken along the line 8--8 ofFIG. 7 and viewed in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations and furthermodifications in the illustrated device, and such further applicationsof the principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to whichthe invention relates.

Referring now more particularly to FIG. 1, there is shown thecombination of a liquid petroleum gas cylinder 10 having an outletaperture 11 threadedly receiving liquid petroleum gas valve 12. Valve 12has a main body 13 with an inlet 14 and an outlet 15. Main body 13 has achamber 18 (FIG. 4) which opens into the inlet passage 16 extendingthrough inlet 14. In addition, chamber 18 opens into the outlet passage17 extending through outlet 15. Outlet 15 is of tubular constructionhaving an internally threaded portion 19 surrounding outlet passage 17with the outlet passage further including a tapered portion 20positioned between internal threads 19 and chamber 18. An annular seat21 surrounds outlet passage 17 and is located between tapered portion 20and internal threads 19.

An annular ring 22 is formed within the valve body and receives movablewall 23 attached to rod 24 rotatably mounted to the valve body. A handle25 is fixedly attached to rod 24 with rotation of the handle and rodresulting in movement of wall 23 either toward or away from ring 22thereby controlling the flow of liquid petroleum through inlet passage16 and then through the chamber and out passage 17.

An externally threaded hollow cylinder 26 (FIG. 3) is threadedlyreceived by threads 19 and has a hexagonally shaped nut 27 integrallyformed thereon. A hollow stem 28 extends through cylinder 26 with thestem including a bullet shaped enlarged head 29 projecting throughannular seat 21 and into tapered portion 20 of outlet passage 17.Cylinder 26 is fragmented in FIG. 2 to illustrate the hollow interior 30of the cylinder through which stem 28 projects. As shown in FIG. 2, theinner end 31 of cylinder 26 projects against the overhanging portion 32of the bullet shaped enlarged head 29 thereby forcing head 29 throughannular seat 21 and into tapered portion 20 as cylinder 26 is threadedinto the valve body. In the prior art devices, a seal is accomplishedbetween head 29 and tapered portion 20 by forcing the bullet shapedenlarged head 29 sufficiently into tapered portion 20 so as to achievemetal to metal contact between head 29 and portion 20. My improvement isto insert an O-ring seal 33 onto the annular seat 21 with the enlargedhead 29 being forced through and against the O-ring seal 33 therebyachieving a fluid tight seal between the enlarged head 29 and taperedportion 20 of the main body of the valve. Hollow cylinder 29 may betightened so as to force the enlarged head 29 against the O-ring 33 withthe enlarged head 29 being spaced at all times away from the innertapered portion 20 thereby preventing scratching or marring of taperedportion 20.

The method of changing a hard nosed liquid petroleum cylinder valve asshown in FIG. 2 to a soft nosed liquid petroleum cylinder valve as shownin FIG. 3 includes the first step of untightening and removing the malehollow valve stem 28 from valve 12. The O-ring seal 33 is then insertedinto the valve onto annular seat 21 with stem 28 then being mounted tothe valve with enlarged end 29 extending through the O-ring and into thetapered portion 20. End 29 of the stem is kept at all times spaced apartfrom tapered portion 20 even though it is adjacent to tapered portion20. The stem is then tightened on the body by threading cylinder 26 intothe body and forcing the enlarged end 29 against the O-ring sealresulting in a seal between stem 28 and valve 12.

Stem 28 is provided with external threads 34 on its outer end tothreadedly receive external pipe 35 (FIG. 1) which may be rigid orflexible and which in turn may be connected to the regulator or otherexternal device. Typically, valve 12 is provided with a safety outlet 36in communication through the inlet passage with the interior of tank 10thereby allowing escape of pressure when the pressure within the tankexceeds the predetermined value. A safety shield 37 is typically mountedto the top end of tank 10 partially enclosing and protecting the valveas well as auxillary equipment, such as, an indicator.

FIGS. 5 and 6 disclose a plate wrench 50 used to tighten the hexagonallyshaped nut 27 (FIG. 3) on cylinder 26. Plate wrench 50 has a main body51 with a first hole 52 extending therethrough for complementarilyreceiving nut 27. In addition, the plate wrench includes a pair ofgrooves 53 and 54 for releasably holding O-ring seals. A pair of O-rings55 and 56 are secured respectively within grooves 53 and 54.

Groove 54 and O-ring 56 will now be described it being understood that asimilar description applies to groove 53 and O-ring 55. The averageinside diameter 57 of groove 54 is greater than the inside diameter ofO-ring 56 thereby requiring the flexible O-ring to stretch in order tobe positioned within the groove. A plurality of projections 59 areformed within groove 54 projecting partially across the groove so as toprevent accidental disengagement of the O-ring with respect to theplate. Groove 54 opens through a recess 60 formed in the end of theplate thereby allowing a person to extend an object such as a finger,into the groove for removing the O-ring therefrom.

Hole 52 has a larger size and configuration 61 on side 62 of the plateas compared to the configuration and size 63 on the opposite side of theplate. That is, hole 52 tapers from one side of the plate to the otherside of the plate thereby resulting in a frictional engagement of thewrench with respect to the nut 27 formed on hollow cylinder 26. The sizeof nut 27 is approximately between the size of hole 52 on side 62 andthe size of hole 52 on the opposite side of the plate.

An additional step of the described method is removing the O-ring sealstored in wrench 50 prior to inserting the O-ring seal into the valvebody. In addition, the stem is extended through the plate wrench priorto mounting the stem to the valve body enabling positioning of nut 27through hole 52. The wrench is produced from plastic and is disposableand as a result, the wrench may be left on the nut after hollow cylinder26 is tightened thereby alleviating the necessity for disengaging theregulator or other external device attached to stem 28. An advantage ofproducing the wrench from plastic is the prevention of sparks resultingfrom a metal wrench and the metal valve. Plate wrench 50 has anapproximate length of 3 inches thereby limiting the amount of torquepractically applied to the hollow cylinder and thereby eliminating thepossibility of metal to metal contact between the enlarged end of thestem and the valve body.

Plate wrench 80 is similar to wrench 50 and is an alternate embodimentthereof. Wrench 80 has a main body 81 with two recesses 82 and 83 formedon one side of the main body. A pair of upraised portions 84 and 85 arepositioned respectively in recesses 82 and 83 to fittingly receiverespectively O-rings 86 and 87. The diameter of upraised portions 84 and85 are greater than the inside diameter of O-rings 86 and 87 therebyrequiring the O-rings to be stretched in order to be fitted onto theupraised portion. Recesses 82 and 83, in conjunction with upraisedportions 84 and 85, thereby form a pair of grooves which receive theO-rings with one of the grooves shown in FIG. 8. The diameters ofupraised portions 84 and 85 decrease from the outer surfaces of theupraised portions 84 and 85, as shown in FIG. 8, thereby retaining theO-rings without requiring projections 59 such as are utilized withwrench 50.

The hexagonally shaped hole 88 extending through main body 81 has alarger size and configuration on one side of main body 81 than on theopposite side in a manner similar as that described for hole 52. Thatis, hole 88 has a smaller size 90 on one side of the wrench as comparedto size 89. In addition, a plurality of projections 91 are provided onthe plate projecting into hole 88 being positioned between the oppositesizes 89 and 90 to provide additional frictional engagement of thewrench with respect to the valve nut 27.

It will be obvious from the above description that the O-ring requiresonly simple installation procedures which may be accomplished in thefield. The method and tool is relatively inexpensive thereby allowingthe conversion of an inexpensive hard nosed connector into a soft nosedconnector for an LP gas valve. The O-rings are coated with siliconthereby providing for a better seal between the enlarged end and thevalve body. The relatively small sized wrenches 50 and 80 areparticularly advantageous when removing the hollow cylinder from thevalve mounted in a confined small space. In many instances, it isimpossible to remove the hollow cylinder with a large wrench due to theworking space available.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiments have been shown and described and thatall changes and modifications that come within the spirit of theinvention are desired to be protected.

The invention claimed is:
 1. In a liquid petroleum valve and tankcombination including a tank for holding liquid petroleum with said tankhaving an outlet aperture, said combination further including a liquidpetroleum valve threadedly received by said outlet aperture, said valvehaving a main body with a chamber formed therein and an inlet passageleading from said outlet aperture to said chamber, said main bodyfurther including an internally threaded outlet tube with an outletpassage extending therethrough opening into said chamber with said valveincluding means mounted to said main body operable to control flow ofliquid petroleum from said tank through said chamber and said outletpassage, said outlet passage including an inner tapered portion and anouter internally threaded portion with an annular seat disposedtherebetween, said valve having an externally threaded hollow cylinderthreadedly received by said internally threaded portion and a hollowstem slidably extending through said hollow cylinder, said stem includesa bullet shaped enlarged head projecting through said annular seat intosaid inner tapered portion being secured therein by said hollow cylinderwherein the improvement comprises an O-ring seal having a circular crosssection seated on said annular seat with said enlarged head forcedthrough and against said O-ring seal effecting a fluid tight sealbetween said enlarged head and said main body by said hollow cylinderforcing said enlarged head against said O-ring seal with said enlargedhead being spaced from said inner tapered portion by said O-ring seal,said stem including a longitudinally extending axis extending centrallythrough said bullet shaped enlarged head and said annular seat, saidhead including a frustoconical outer smooth surface projecting throughsaid annular seat which is formed by a first annular surface and asecond surface perpendicularly arranged to said first annular surfaceand said axis, said frustoconical outer surface spaced apart from saidfirst annular surface and said second surface by said O-ring seal whichis located between said head and seat and forced against said firstannular surface and said second surface by said head providing at leastthree continuous surfaces of sealing contact on said O-ring seal andbetween said O-ring seal and said head and said annular seat and furtherspacing apart all portions of said head from said main body of saidvalve.